Pressure sensitive record material



PRESSURE SENSITIVE RECORD MATERIAL Barrett R. Green, Dayton, Ohio, assignor to The National Cash Register Company, Dayton, Ohio, in. corporation of Maryland No Drawing. Original application November 8,

1947, Serial No. 784,938. Divided and this application November 10, 1948, Serial No. 59,424

12 Claims.

This invention relates to improvements in pressure-sensitive record material. This application is a division of the pending application of Barrett K. Green, Serial No. 784,938, filed November 8, 1947, for Pressure-sensitive record material.

The principal object of this invention is to provide a pressure-sensitive record material on which a mark of distinctive color may be produced by the mere application of localized pressure and which is not subject to the disadvantages inherent in the pressure-sensitive record material disclosed in United States Letters Patent No. 2,299,693, patented October 20, 1942, on the application filed b Barrett K. Green on February 23, 1940. That patent discloses a pressure-sensitive record material including the combination of an insulating medium, a rupturable solid material such as gum dammar, having included therein interpersed droplets of a plurality of liquid reagents, which are chemically reactive to produce a distinctive color in the record material at the points of application of localized pressure thereto, such pressure rupturing the insulating medium to permit chemical reaction between the two liquid reagents. The two reagents disclosed in this patent are gallic acid and ferric ammonium sulphate, each dissolved in glycerine. These reagents are ionized by the glycerine, which constitutes an ionizing medium, and the chemical reaction proceeds by interchange of ions when the two solutions are allowed to mix, upon the rupture of the insulating medium. The reaction disclosed in that patent depends upon the presence of the reagents in an ionizing medium. However, any available ionizing medium is hygroscopic, with the result that the record material made in accordance with this patent is sensitive to an excess of moisture, and conditions of high humidity may cause the insulating medium to cease to be efiective, with the result that the chemical reaction takes place without any application of localized pressure, and the record material is stained and discolored, so that it ceases to be useful.

As stated above, the principal object of the present invention is to provide a pressure-sensitive record material that is not subject to the defacts and disadvantages of that disclosed in Patent No. 2,299,693, as indicated above.

Another object of the present invention is to provide a record material upon which a mark of distinctive color may be produced, at the points of application of localized pressure thereto, by such mere application of localized pressure, and

which will not become discolored or stained due to the efiect of light, atmospheric conditions, or aging.

In short, it is the object of this invention to provide a pressure-sensitive record material in which the mark of distinctive color will be produced only at the points of application of localized pressure, and at no other points, and under no other conditions.

Another object of this invention is to provide a pressure-sensitive record material in which the mark of distinctive color is produced by the chemical reaction of color-forming reactants, in the absence of any liquid ionizing medium therefor.

A further object of this invention is to provide In general, the present invention contemplates a pressure-sensitive record material comprising, in combination, a plurality of adsorption coloriorming reactants, such reactants being so selected that they react, in the absence of a liquid ionizing medium for the reactants, to form a distinctive color when brought into adsorption contact with each other, and a solid insulating medium insulating said reactants from colorforming, reaction contact with each other. Upon application of localized pressure to the record material, as by drawing a stylus across it, the insulating medium is ruptured at the points of application of said localized pressure, and such rupture permits color-forming reaction contact between the reactants at such points, in the absence of any liquid ionizing medium for said reactants. The result is that a mark of dis tinctive color is produced by the mere application of localized pressure.

The color-forming reaction employed is of the, so-called, adsorption type in which an inorganic material causes a color change in an organic material in adsorption contact therewith. Of the reactant materials employed the organic material is an electron donor aromatic compound having a double bond system which is convertible to a more highly polarized conjugated form upon taking part in an electron acceptor-donor solid surface chemical reaction, giving it a distinctive color, and the inorganic material a material which is an acid relative to the orga material so as to be an electron acceptor in adsorption contact therewith. Both materials are in fine particle form in order to furnish a large reactant surface area per unit area of the record material which enhances the depth of color per unit area of the record'material.

In this invention, both of the color-forming reactants, as well as the insulatingmedium, are in the solid state, and the color-forming reaction takes place upon mere contact of solid. particles of the reactants. A pressure-sensitive record material may be provided in which the solid particles of a plurality of color-forming reactants are dispersed in a solid insulating medium, which insulates the particles from color-iorming r action ,contact with each other. The rupture of thissolid insulating medium by the application of localized pressure permits the solid particles of color-forming reactants to react with each other, at thepoints of application of such pressure, to produce the mark of distinctive color. According to one form of this invention, solid particles of one -of the color-forming reactants are carried by and dispersed in a solid insulating medium, to whicha-coating of solid particles of another color-forming reactant is applied. In this case, the application of localized pressure ruptures the solid insulating medium at the points of application ofsuch pressure and brings about color-forming reaction contact between the solid particles of color-forming reactants at such points, thus producing the mark of distinctive color. Preferably, this pressure-sensitive record material includes a baseweb, such as a fibrous web of paper or the like, to which the coating of solid insulating medium and the color-forming reactants is applied.

Since it is diliicult to showprecisely the spatial relationship between the solid particles of colorforming reactants, the solid insulating medium, and the base web, it ispreferred not to attempt to illustrate any embodiment of this invention by drawings.

Following there will :be describeol an embodiment of this invention, by means of which the objects of the invention have been successfully attained. V v V ,A base web of paper has appli d thereto a coating including casein as the solid insulating medium and two color-iorming reactants; name" 1y, kaolin and the compound o-hydroxybenzalacetophenone, having thestructure This record material comprises solid particles of kaolinand o-hydroxybenzalacetophenone in sulated from-color-forming reaction contact with each other "by casein as the solid insulating medium. The record material is normally light yellow in color, and application of localized pressure thereto ruptures the insulating medium at the points of applicationgor" such pressure, permitting color-forming reaction contact between the particles at such ,points and producing a reddish-yellow mark.

When these ingredients are applied to the paper as a coating thereon. ;:su,ch coating preferably shouldweighsabout .0023 -pound persquare foot of surface and may have a thickness of the order of from .0305 to .901 inch. The thickness of the coating varies of course, with the treatment to which the record material is subjected in finishing. The solid particles of kaolin in this record material may be of about the order of ten microns in diameter, although considerable variation in particle size is possible without any ill effects. Particle size of the o-hydroxybenzalacetophenone is largely determined by the method of application of that ingredient. The particles of these reactants may be as large as ten microns in diameter-and frequently are much smaller.

a method that has been used successfully to make the pressure-sensitive record material described above is as follows: A slurry of kaolin and water was-prepared including fifty parts by Weight of kaolin to fifty parts by weight of water, and a small amount of a suitable dispersing agent, such as sodium metaphjosphate, for instance, in the proportion of 0.075% byweight-twasadded-to facilitate the dispersion or the particlesrofkaolinthrou hout the slurry. The addition of this dispersing, agent reduces the viscosity'of the slurry considerably, thus facilitating its mixing and application and also preventing the settling of the solidparticles of kaolin. A 20% by weight solution of casein in water was formed were,

dispersing the casein in cold water by stirring for fifteen minutes at room temperature and, thenyhcatingup to 6 0 ,degreescentigrade. Five parts by weight of a,28% ammonium hydroxide solution-that is, one having ;a specificgravity of 253 ea, at

were then added to thehotcasein-solution, which was stirred for about fifteenminutes and allowed town! to room temperature. The kaolin slurry and the alkaline casein solution were gthen thoroughly mixed and blended'in theratio of ten parts by weight of .kaolinsto one part of. casein, and, at this stage, asma-ll percentage-4% instance, about 0.65% by weight-of 'tributyl phosphate in a1cohol,.or other anti foaming agent, was added. This mixture of {the kaolin slurry and the casein solutionwas then applied :as a coating to the paper, and :thexlcoated paper was dried and calendered or treated in iflllYJdESil'Qd way to give the proper surface finish. A solution in toluene of about :3% :by weight of,o

hydroxybenzalacetophenone .was .then applied-to the'coated side of the paper, the excess of this solution was removed in anyisuitable way, as by passing under a doctor .blade, andzthen the treated paper was driedto-evaporatethe toluene and was ready for use.

Organic film-forming hydrophilic colloid substances such as gelatin, methyl-cellulose, starch, polyvinyl alcohol, and animal glue may be sub= stituted'for the casein.

Attapulgite, pyrophillite, iBentonite, ,Halloyeite,

magnesium 'trisilicate and ;zinc sulphide are typical inorganic compounds whichgmay-gbe used. instead of kaolin. V

The methods endprocess of -makin thepressure-sensitive record material disclosed herein are not claimedin this application but are disclosed and claimed in the pendingapplicationof Barrett K. Green,=$erial 'No. 78%.939, filed November 8, 1 947, for Process ;for making pressure-sensitive record material, and in the division thereof, Serial No. 63213, filed Decent ber 2, 194.8.-

area-4'74 It is understood that the pressure-sensitive record material described herein is susceptible of considerable variation without departing from the spirit of the invention.

What is claimed is:

1. Pressure-sensitive record material including the combination or" a supporting member, a plurality of adsorption color-forming reactants in the solid state, at least one of said reactants being an inorganic compound and at least another of the reactants being an organic compound, so selected as to react in the absence of a liquid ionizing medium for the reactants to form a distinctive color when brought into adsorption contact with each other, disposed in proximity to each other, and a solid insulating medium, derived from an organic film-forming hydrophilic colloid substance, insulating said reactants from color-forming reaction contact with each other, the application of localized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit color-forming reaction contact between the reactants at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of the color-forming reactants being the organic compound hydroxybenzalacetophenone, having the structure and the inorganic reactant being in fine particle form providing a large adsorbent surface area which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with said organic compound, said organic compound being adsorbable upon the inorganic material.

2. The record material of claim 1 in which the inorganic color-forming reactant is kaolin.

3. The record material of claim 2 in which the solid insulating medium is casein.

4. Pressure-sensitive record material including the combination of a supporting member, solid particles of a plurality of adsorption color-forming reactants disposed in oontiguity to each other, at least one of the reactants being an inorganic compound and at least another one of the reactants being an organic compound and a solid insulating medium, derived from an organic hydrophilic film-forming colloid substance, insulating said solid reactant particles from coloriorming reaction adsorption contact with each other, said reactants being so selected as to react to form a distinctive color when particles of each are brought into contact, the application of localized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit colorforming reaction contact of the solid reactant particles at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of the color-forming reactants being the organic compound o-hydroxybenzalacetophenone, having the structure and the inorganic reactant being in fine particle form providing a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound;-

inorganic color-forming reactant is kaolin.

6. The record material of claim 5 in which the solid insulating medium is casein.

'7. Pressure-sensitive record material includingv the combination of a supporting member, a solid insulating medium derived from an organic filmforming hydrophilic colloid substance, solid particles of a first adsorption color-forming reactant dispersed therein and solid particles of a second adsorption color-forming reactant deposited thereon, said solid insulating medium insulating said solid reactant particles from color-forming reaction adsorption contact with each other, one of said reactants being an inorganic compound and the other of said reactants being an organic compound and said reactants being so selected as to react, in the solid state, to form a distinctive color when brought into adsorption contact with each other, the application of localized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit color-forming reaction contact of the solid reactant particles at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, the second color-forming reactant being the organic compound o-hydroxybenzalacetophenone, having the structure and the first color-forming reactant being the inorganic material in fine particle form providing a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound, and said reactants being adsorbable one upon the other.

8. The record material of claim 7 in which the first color-forming reactant is kaolin.

9. The record material of claim 8 in which the solid insulating medium is casein.

10. Pressure-sensitive record material including the combination of a base web and a coating thereon, said coating including a plurality of adsorption color-forming reactants in the solid state, so selected as to react in the absence of an ionizing medium to form a distinctive color when brought into adsorption contact with each other, and disposed in proximity to each other, at least one of said reactants being an inorganic compound and at least another of said reactants being an organic compound adsorbable on the inorganic compound, and a solid insulating medium, derived from an organic hydrophilic film-forming colloid substance, insulating said reactants from color-forming reaction contact with each other, the application of localized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit color-forming reaction contact between the reactants at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of the color-forming reactants being the organic compound o-hydroxybenzalacetophenone, having the structure 7 J and the inorganic reactant being; inurganic" ma REFERENCES CITED- in fine: Particle Pmviding large The foilbwing references are or record in the adsorbent surface area. and which is an acid re19;-- m of this tive tuthe organiccompound. saas-toube ail-electron acceptor when in adsorptidn. contact with FOREIGN PATENTS: said r ani c mp und- Number Country Date 11. The record material of: claim: 10. 'inzwhich 550,332 Great Britaih Jan.- 4,1943

the inorganic color-forming reactant is: kaolin.

12. The record'material' of? claim 11 imwhich the" solid insulating medium is casein;

BARRETT. KLGREEN. 

1. PRESSURE-SENSITIVE RECORD MATERIAL INCLUDING THE COMBINATION OF A SUPPORTING MEMBER, A PLURALITY OF ADSORPTION COLOR-FORMING REACTANTS IN THE SOLID STATE, AT LEAST ONE OF SAID REACTANTS BEING AN INORGANIC COMPOUND AND AT LEAST ANOTHER OF THE REACTANTS BEING AN ORGANIC COMPOUND, SO SELECTED AS TO REACT IN THE ABSENCE OF A LIQUID IONIZING MEDIUM FOR THE REACTANTS TO FORM A DISTINCTIVE COLOR WHEN BROUGHT INTO ADSORPTION CONTACT WITH EACH OTHER, DISPOSED IN PROXIMITY TO EACH OTHER, AND A SLOID INSULATING MEDIUM, DERIVED FROM AN ORGANIC FILM-FORMING HYDROPHILIC COLLOID SUBSTANCE, INSULATING SAID REACTANTS FROM COLOR-FORMING REACTION CONTACT WITH EACH OTHER, THE APPLICATION OF LOCALIZED PRESSURE TO THE RECORD MATERIAL RUPTURING SAID INSULATING MEDIUM AT THE POINTS OF APPLICATION OF SUCH PRESSURE TO PERMIT COLOR-FORMING REACTION CONTACT BETWEEN THE REACTANTS AT SUCH POINTS, WHEREBY A MARK OF DISTINCITVE COLOR IS PRODUCED BY MERE APPLICATION OF LOCALIZED PRESSURE, ONE OF THE COLOR-FORMING REACTANTS BEING THE ORGANIC COMPOUND OHYDROXYBENZALACETOPHENONE, HAVING THE STRUCTURE 